Electrical connector and circuit board mounting system

ABSTRACT

A zero initial insertion and full zero retraction force connector is provided including a housing and a folded leaf spring inserted into the housing. The leaf spring has various portions defining a pin, a socket, and a spring member. The spring 5 member extends from one side of the socket above the housing and is anchored in the housing at its free end. Depression of the spring member when two connectors mate causes one wall of the socket to move towards an opposing wall thereby to make stable electrical and mechanical contact with an inserted pin during the last portion of the insertion stroke in which the pin is inserted into the socket.

United States Patent 1 Rosen 1 Dec.2, 1975 [75] Inventor: Harold Rosen,Nashua, NH.

[73] Assignee: Sanders Associates, Inc., Nashua,

[22] Filed: Sept. 5, 1974 [21] Appl. No.: 503,216

22,981 9/1969 Japan 339/75 MP Primary ExaminerJoseph H. McGlynnAttorney, Agent, or Firm-Louis Etlinger; Robert K. Tendler [57] ABSTRACTA zero initial insertion and full zero retraction force connector isprovided including a housing and a folded leaf spring inserted into thehousing. The leaf spring has various portions defining a pin, a socket,and a spring member. The spring 5 member extends from one side of thesocket above the housing and is anchored in the housing at its free end.Depression of the spring member when two connectors mate causes one wallof the socket to move towards an opposing wall thereby to make stableelectrical and mechanical contact with an inserted pin during the lastportion of the insertion stroke in which the pin is inserted into thesocket.

30 Claims, 7 Drawing Figures LAT RAL IIIIII" III IDISPLACEM ENT,44

Illilllll II/II) US. Patent Dec. 2, 1975 Sheet 1 of3 3,923,361

LATERAL DISPLACEMENT,44

FIGZ

US. Patent Dec. 2, 1975 Sheet 2 of3 3,923,361

mm F CONNECTOR COMPONEN US. Patent Dec. 2, 1975 Sheet 3 of3 3,923,361

FIG. 7

CONDUCTIVE STRIP, 106

O l 1, i J

PRINTED CIRCUIT ELECTIRHCAL CONNECTOR AND lCllRlClJl'll BOARD MOUNTINGgYSTl'Jll/ll This invention relates to electrical connectors and moreparticularly to a zero initial insertion and full zero retraction forceconnector.

One of the most important problems associated with multi-pin electricalconnectors is the problem of the force necessary to cause the mating ofthe male and female portions of the connector and the separation ofthese portions. it will be appreciated that if 2 ounces of force isrequired to insert each pin, for connectors having upwards of 200 pinsthe mating force is indeed considerable. Moreover, and perhaps moreimportantly, when the connections are pulled apart a large force isnecessary to separate the two portions of the connector. The insertionand retraction problem associated with multi-pin connectors isparticularly severe in the interconnection of printed circuit boards andcables having a large number of conductors. The subject invention solvesthis problem by providing that the force applied to a pin from oneconnector inserted into the socket of a mating connector be zerominimized during the mating and separation of the connectors.

The problem of the force necessary to connect and disconnect matingconductors centers around not only the convenience factor but alsoaround the necessity for preventing the buckling of the pins. in highdensity packaging configurations it is desirable to make the connectorpins thin. However, the pins oftentimes buckle when inserted. Thesubject invention solves the buckling problem by restricting thecompressive or buckling forces on the pin to occur during only the lastfew mills of the insertion stroke, thereby effectively applying thebuckling force to the extremely short uninserted pin section remaining.This totally eliminates pin buckling as a source of failure whileadditionally retaining the wipe action necessary for self-cleaning.Moreover, pin damage often occurs due to the jerk, or sudden relaxationof force upon separation. The subject connector described hereinafteralso eliminates this potential for damage by quick release of the pinduring separation.

By way of background, as described in connection with US. Pat. No.3,474,387, prior art connectors generally utilize contacts which are inthe form of deflectable simple beams in the female portion of theconnector which are deflected into contact with the pins or posts from amating male connector. The deflection of the simple beam is ordinarilyaccomplished by a cam eccentrically mounted relative to the center lineof the connector and rotatable about an axis normal to the plane withinwhich the beams are deflectable. As noted in the above mentioned patent,one of the major (lifticulties with the external cam actuated connectoris that access to the cam is oftentimes approached from the lengthwiseend of the connector instead of being accessable from the same directionin which the force is applied to cause mating of the male and femaleportions of the connector. in the case of printed circuit boards whatthis means is that when the circuit board is inserted it is necessary toactuate the cam from a direction which may be obscurred by either thewalls of the cavity into which the circuit board is inserted or by otherequipment or electronic components. Thus there is no easy access to thecam actuating member for either carnming the deflectable beams intocontact with 2 the projecting pins or, for camming them away from thepins in the case of removal of the printed circuit board.

in the above mentioned patent, there is illustrated a two-part connectorin which vertically mounted spring members are camrned into contact witha portion of the circuit board containing the contact pads. it will beappreciated that this connector is a two-part connector in which acarnming member contacts a spring member in order to urge it intocontact with an adjacent male contact when the two portions of theconnectors are squeezed together. What in effect has been providedtherefore is a separate camming member. Moreover, the connector of thispatent is not a hermaphroditic connector in the sense that inhermaphoditic connectors the same connector assembly is used as a maleand female member.

Perhaps more importantly the thickness of the spring member in the abovementioned patent is such as to require a large amount of force in orderto bring the spring member into contact with a contact pad on theinserted printed circuit board. The force necessary to make contact isdependent on the elasticity of the spring member which in turn isdependent at least in part on the thickness of the spring. It will beappreciated that the same spring member which is deflected to makecontact with the inserted contact pad also extends outwardly of theconnector to provide a contact pin or post. it is important for thestructural stability of the pin that it be of sufficient thickness towithstand buckling. Since the deflected member and the pin are made fromthe same piece of metal, the resulting spring member in the connectorhousing is relatively stiff. This in turn results in the necessity ofapplying a relatively high force in order to deflect the spring memberinto contact with an inserted conductor. While this force may not beexcessive in the case of one or two pins, the force is multiplied by thenumber of pins and therefore becomes a considerable problem when, forinstance, 200 or more pins are provided.

The force necessary to deflect the spring member is also important whenconsidering wear and reliability. This problem can perhaps be morereadily appreciated by referring to US. Pat. No. 3,750.085. in thispatent a spring is deflected into contact with an inserted conductor bythe squeezing together of two parts of the connector. in this patent thespring member and pin are also from the same piece of metal. As before,the force necessary is directly related to the thickness of the springmember. When this force is excessive the point of contact between theend of the spring and the upper portion of the connector causes thespring to dig into the upper portion of the connector thus weakening itand/or scoring it by an amount directly proportional to the forcenecessary to establish the requisite contact force. In this connection,it will be appreciated that a thinner spring member would dig in lessduring the mating procedure and reliability would be improved.

The aforementioned problems are solved by the subject electricalconnector which, because of its folded spring configuration, requiresapproximately onefourth the force normally used to establish therequisite contact force. The folded construction also provides a thickpin depending from the connector body which is integral to and is a partof the deflectable spring member. Because of the folding of the springto form the pin, the pin is rigid and resists buckling while the springportion, being only one-half the thickness of the pin is relatively easyto deflect and therefore requires less in the way of deflection force.The connector is also unitary in construction in the sense that it isnot a two-part connector; it is hermaphroditic in the sense that thesame connector is utilized both as a male and female member; and it isan initial zero insertion force and a full zero retraction forceconnector which permits easy insertion and extraction.

In one embodiment, the subject connector includes a housing having ahorizontal channel in its upper face. A vertical channel extends throughthe body of the connector and communicates both with one end of thehorizontal channel and with the bottom face of the connector housing.Within the horizontal and vertical channels is placed a folded leafspring structure. The vertical channel has a wider upper portion and thefolded leaf spring which projects down through the lower portion to formthe pin of the connector is separated in this widened portion. One halfof the leaf spring is stationary and rests against a sidewall of thewidened portion. The other separated portion of the leaf springordinarily resides against an opposing vertical wall of the widenedportion and is adapted to move into contact with an inserted pin whenthe bottom of a similarly constructed connector body impinges upon aportion of this leaf spring which projects above the top of theconnector body through the upper channel. When the projecting portion ofthe spring is flattened, the laterally displaceable portion of the leafspring within the vertical widened channel is pressed into contact withthe downwardly depending pin from the connector immediately above.

During the first part of the insertion of a pin into the female socketportion of the connector the pin is free and no electrical or mechanicalcontact is made. During the last few mills of insertion the pin wipesagainst the socket as mechanical connection is made which results in acleaning action. It will be appreciated that during the majority of theinsertion stroke no force or load is applied to the pin, while duringthe last few mills of insertion, since force is necessary to make boththe electrical and mechanical connection, the pin is loaded. Thus theterm zero initial insertion force refers to a lack of force during theinitial insertion of the pin. Since a load is only applied to the pinafter the pin is almost fully inserted, pin buckling is minimized because the load is applied close to the base of the inserted pin wherethe lever arm is shortest and the mechanical stability is highest.

In this connector, there is no two-part body construction and there isno separate camming surface to urge the leaf spring into contact with anadjacent inserted conductor. Rather, the portion of the leaf springprojecting above the connector body, having been urged in a downwarddirection causes a translation of the laterally displaceable portion ofthe leaf spring into contact with the inserted conductor post. Finalelectrical and mechanical connection is maintained by the clampingtogether of the two adjacent connector housings. It will be appreciatedtherefore that the connector is of extremely simple construction inwhich a leaf spring is folded on itself along one portion and isseparated from itself at another portion. Actuation takes place by flabtening a portion of the spring extending above its hous ing. The leafspring is easily formed and is also easily inserted into the conductorbody to form the aforementioned unitary hermaphroditic connector.

The resulting electrical connector has a projecting pin, which is doublethe thickness of the leaf spring. This, plus the fact that the load isapplied to the pin close to its base only after almost completeinsertion provides for anti-buckling protection. At the same time onlyone-half the thickness of the projecting pin or post is utilized in theleaf spring portion of the connector. This provides that only one-fourthof the force ordinarily necessary is exerted in achieving full contactpressure.

in operation, the laterally displaceable portion of the leaf springresides against one wall of the vertical channel thereby to giveclearance for the inserted pin from an adjacent connector without anyfrictional force being applied to this pin. As the pin is insertedfurther into the connector the bottom portion of the connector body fromwhich the pin depends presses against the extending spring portion whichprojects upwardly above the top surface of the bottom. connector. Whenthe pin is near fully inserted, the bottom of the upper connectordepresses the upwardly extending spring portion thereby to laterallydisplace the leaf spring member into contact with the inserted pin tomake the electrical connection. The mechanical connection is completedby clamping together the two connectors. Removal is quite simple sincerelease of the two connectors results in a upward force being applied tothe upper connector by the depressed leaf spring from the lowerconnector. This force initially aids in the separation of theconnectors. After a predetermined separation the pin is completely freeof frictional engagement with the lower connector leaf spring and isthereafter easily withdrawn. Thus, the compressed spring functions toaid in the removal of the upper connector unlike the two-part connectorsof the prior art.

The particular hermaphroditic configuration also makes possible a newmethod of interconnecting printed circuit boards. in the usualconfiguration, printed circuit boards have end connectors which matewith rackmounted connectors when the board is inserted into place. Thisarrangement requires a separate rack mounted connector strip whichincreases the weight of the apparatus.

With the subject connector, printed circuit boards may be interconnectedin a stacked arrangement without the use of separate rack mountedconnectors. This results not only in weight reduction but also in amechanically stable selfsupporting package.

It is therefore an object of this invention to provide a hermaphroditiczero initial insertion and full zero retraction force electricalconnector of unitary construction;

It is another object of this invention to provide an electricalconnector in which the insertion force necessary to provide sufficientcontact engagement force is minimized.

It is yet another object of this invention to provide a low costmultipin connector comprised of only a housing and a spring having afolded configuration.

it is a further object of this invention to provide a connector systemutilizing hermaphroditic components in which each component carries afolded leaf spring having a portion thereof extending above a surface ofthe component such that communication between the surface of onecomponent and the extended spring portion upon mating of the connectorcomponents results in the displacement of a portion of the spring in adirection orthogonical to the applied force.

It is a further object of this invention to provide a zero initialinsertion and full zero retraction force electrical connector in whichno separate camming member is utilized.

It is a yet still further object of this invention to provide animproved method and apparatus for interconnecting printed circuit boardswhich reduces the weight of the connected configuration by eliminatingthe necessity for a card rack.

It is a yet still further object of this invention to provide a zeroinitial and full zero retraction force electrical connector which ismore reliable and less prone to failure.

It is a yet still further object of this invention to provide ahermaphroditic zero initial insertion and full zero retraction forceelectrical connector having the pin and socket member being formed fromthe same leaf spring, with the pin portion having double the thicknessof the socket portion thereby to prevent buckling of the pin whileallowing increased flexability of portions of the socket which isactuated into frictional contact with a mating male member.

These and other objects of this invention will be better understood inconnection with the following description in view of the appendeddrawings in which:

FIG. 1 is a cross sectional and partial perspective view of the subjectconnector illustrating a poriton of the connector component forming themale member inserted into a socket of the component forming the femalemember;

FIG. 2 is a partial cross sectional drawing illustrating a portion ofthe leaf spring of the connector which extends above the top surfacethereof;

FIG. 3 is a perspective view of printed circuit boards stackedvertically and connected with the subject connector;

FIG. 4 is a partial sectional and perspective view of the circuit boardand connector illustrated in FIG. 3;

FIG. 5 is a partial exploded view illustrating the method of replacementof circuit boards and connectors with the configuration illustrated inFIG. 3;

FIG. 6 is a partial perspective and exploded diagram illustrating theuse of the subject connector in a conventional end-connectorconfiguration for circuit board applications; and

FIG. 7 is a partial perspective and sectional view illustrating thesubject connectors connected to a circuit board in an end-connectorconfiguration without the use of additional connecting leads.

Referring now to FIG. 1 a hermaphroditic connector 10 is illustrated ashaving a folded leaf spring member 12 inserted into a verticallyextending cavity 14 in connector housing 11. Cavity 14 has a narrowportion 16 and a widened portion generally indicated at 18. The springmember 12 extends upwardly and outwardly of cavity 14 and includesseparated spring portions 19 and 20 which ordinarily rest against thewalls making up the widened portion 18 of cavity 14. A horizontalportion 21 of spring member 12 projects outwardly of the connectorhousing 11.

A second horizontally extending portion 22 of leaf spring member 12extends to the right in a horizontal channel 24 cut in the top surface26 of housing 11. Spring portion 22 includes a bent portion 28 whichextends above face 26 of the connector 10. Additionally, an additionalbent portion 30 is provided between spring portions 19 and 28.

6 Horizontal forces (F generated by spring portion 28 of spring member12 is closely approximated by the simple equation set out hereinafter,

E= Youngs Modulus '-w here The vertical force (F,,) is approximated bythe following equation:

8 E I Where F K K (9, change in curvature of radiused portion) H stherefore expressed by:

. Kl K v A similarly configured connector 36 is located immediatelyabove connector 10 and has a downwardly depending folded spring portionforming a pin or post 38 such that connector 36 functions as the maleconnector.

As can be seen from FIG. 1 the portion of the spring projecting throughcavity portion 16 is of a double thickness, 2w, as compared to thethickness of the separated spring portions 19 and 20, e.g. w. Asmentioned hereinbefore, the 2w width provides mechanical stability forthe pin while the 37 1w width of spring portion 19 provides forincreased flexability of this member, thereby to reduce the force, Fnecessary in deflecting this member into contact with an inserted pin orpost.

It will be appreciated that spring portion 21 extending outwardly of thehousing, may be provided with any suitable means of making electriccontact thereto such as the threaded screw 40, or a conductive strip(not shown) continuing along the outside of the conductor housing tointersect a printed circuit board. Additionally it will be appreciatedthat either spring portion 21 or spring portion 22 may be made to extendoutwardly of the housing for convenient connection as desired. In anembodiment to be described in connection with FIG. 4, there need be noprojecting portion, as the connection to the various spring members ismade at the respective pins.

In operation, connector 36 is moved downwardly with respect to connector10 such that pin 38 is inserted between the separated spring portions 19and 20. It will be appreciated that there is provided enough clearancebetween these spring portions to permit the insertion of the pin withoutfrictional contact. At a certain point in the insertion of pin 38 abottom surface 42 of the connector 36 impinges upon the top surface ofspring portion 28 deflecting it downwardly with a force F The downwarddeflection of this spring portion results in the lateral displacement ofspring portion 19 which contacts pin 38 with a force F derived from theprevious equations.

It will be appreciated that connectors 10 and 36 may be clamped togetherin any convenient manner thereby to form a stable electrical andmechanical contact between spring member 12 and pin 38. Removal orseparation of the two connectors is accomplished by removing theaforementioned clamping means such that spring portion 19 returns to itsinitial rest condition along side the wall of the widened portion 18.

Because of the folded configuration of the spring member 12approximately one-fourth of the force, F is necessary to create apredetermined contact force as compared to connectors in which thebendable beam is made of the same thickness as the pin extendingtherefrom.

Referring now to FIG. 2 a cross-section of a portion of connector isillustrated showing that the angle 6 subtended by the ends of the curvedportion 48 and 50 may be varied as desired. It has been found, however,that angle 0 in a preferred embodiment is preferably 90 to maximizelateral deflection.

Referring now to FIG. 3, with connectors of the type described, printedcircuit boards 56 may be arranged in a stacked configuration andinterconnected by the subject connectors. The connectors illustrated bythe reference characters 60 are located in a unitary elongated connectorbody as shown. The sandwich structure illustrated is accomplished bythroughbolting the sandwiched structure with the bolts 62.

Interconnection is accomplished, as illustrated in FIG. 4, by theplacement of a printed circuit board 64 between two connectors,illustrated in this figure by reference characters 66 and 68. On thebottom of printed circuit board 64 is a conductive strip 70 which is inelectrical contact with contact pin 72 from connector 66. The connectionis most easily made by creating a hole in both the printed circuit boardand its conductor and inserting the pin from connector 66 through thishole. If the hole is throughplated, no further connecting means may benecessary. Alternatively the pin may be soldered, braised or otherwiseelectrically connected to the conductor on the printed circuit boardafter insertion of the pin through the hole. This connection methodestablishes an electrical connection between conductor 70 and a springmember 74 carried by connector 68 by virtue of the insertion of pin 72into connector 68. These interconnections can obviously be selectivelymade such that selected conductors of one printed circuit board may beconnected to selected conductors of the circuit board either above orbelow it.

Referring to FIG. 5, it will be appreciated that defective circuitboards may be replaced by another circuit board-connector combinationillustrated by the combination of circuit board 64 with connector 66.This provides a convenient stacking and replacement system for circuitboards which eliminates the necessity of a separate rack mountedconnector strip.

The subject connector can also be used in a conventional printed circuitboard connector system as illustrated in FIG. 6, in which a printedcircuit board 80 may be provided with the subject connector illustratedby the reference character 82, in which the connector is mounted at oneend of the circuit board. Alternatively, any suitably configured malepin connector strip may be mounted on and connected to the printedcircuit board, it being understood that use of the subject connector isconvenient since only one lot of connectors need be ordered for both theprinted circuit board connector and the rack mounted connector. In thismounting system, the subject connector is also adapted as a rack mountedconnector strip 84 which is bolted to the rack into which the printedcircuit board is to be inserted.

Connector 82 may have its individual conductors connected to printedcircuit board in the manner illustrated, e.g. by connecting wires 86from spring extensions 88 to contact pads 90 on the circuit board.Alternatively, as illustrated in FIG. 7, any projecting portion of aleaf spring may be inserted into an appropriate hole in the circuitboard to eliminate the necessity of separate wires. For example, in FIG.7 pin projects through through-plated hole 102 in printed circuit board104 and is connected to a conductive strip 106 to mount the connector onthe circuit board as well as connect it thereto.

Referring back to FIG. 6, the circuit board may be secured to the rackmounted connector by bolts such as the bolt illustrated at 92. It willbe appreciated that unlike the aforementioned cam-actuated releasemechanisms the head of the bolt is accessable along the same directionas the direction of insertion of the printed circuit board thereby tofacilitate connector mating.

What has been provided, therefore, is a unitary, initial zero insertionforce and full zero retraction force, hermaphroditic connector having afolded spring configuration for providing both the male and femalemembers of the connector. In one embodiment the folded spring is 24 X 24mills which is precisely the standard pin dimensions for printed circuitboard connectors. Because the female portion of the connector is onlyone-half as thick as the male portion, the force necessary to makeadequate frictional contact is minimized. Moreover, for added strengththe folded portion of the spring member in its housing provides forconsiderable structural stability of the pin. It is obvious that thespring member can be made of any suitable spring material such asberyllium copper, spring brass, etc. and may take on any convenienthousing configuration to accomodate cables as well as printed circuitboards.

Although a specific embodiment to the invention has been described inconsiderable detail for illustrative purposes, many modifications willoccur to those skilled in the art. It is therefore desired that theprotection afforded by Letters Patent be limited only by the true scopeof the appended claims.

I claim:

1. An electrical connector comprising: a housing and an electricallyconductive spring member, said spring member folded on itself to providea pin and separated from itself to form a socket, one portion of thespring member forming a laterally deflectible wall of said socket andincluding an extension having a bent portion, said spring member beingmounted in said housing with said pin extending from one surface of saidhousing, said bent portion extending above a second surface of saidhousing and means for deflecting said one portion upon towards anopposite wall of said socket upon depression of said bent portion.

2. The connector of claim 1 wherein said folded portion includes twospring portions fixedly attached one to the other.

3. The connector of claim 1 wherein said housing is made from a solidblock of material having a vertical channel with narrow and widenedportions communicating with opposing surfaces of said block, and ahorizontal channel 4. The conductor of claim 1 wherein said extensionextends substantially at right angles to said one spring portion.

5. The connector of claim 4 wherein said extension includes a furtherradiused portion between said bent portion and said one spring portion.

6. The connectorof claim 4 wherein said bent portion is radiused.

7. The connector of claim 6 wherein the angle subtended by said radiusedbent portion is 90.

8. An electrical connector comprising a housing, a spring member foldedon itself to provide a pin and separated from itself above the foldedportion to form a socket, one portion of the spring member forming awall of said socket, being deflectable towards an opposite wall, saidspring portion including an extension having a bent portion, said springmember being mounted in said housing with said pin extending from a faceof said housing and said bent portion extending above another face ofsaid housing, the free end of said bent portion being fixedly attachedto said housing, and means for deflecting said one portion responsive todepression of said bent portion.

9.. The connector of claim 8 wherein the folded portion of said springmember includes two spring portions fixedly attached one to the other.

lb. The connector of claim 8 wherein said housing is made from a solidblock of material having a vertical channel with narrow and widenedportions communicating with opposing surfaces of said block, and ahorizontal channel communicating with the widened portion of saidvertical channel and one of said opposing surfaces, said spring memberbeing inserted into said channels.

ll. The connector of claim 8 wherein said extension extendssubstantially at right angles to said one spring portion.

12.. The connector of claim ll wherein said extension includes a furtherradiused portion between said bent portion and said one spring portion.

113. The connector of claim 11 wherein said bent portion is radiused.

14. The connector of claim l3 wherein the angle subtended by saidradiused bent portion is 90.

15.. A hermaphroditic zero initial insertion and zero retraction forceconnector comprising:

a housing; and,

an electrically conductive spring member having a portion folded onitself, two additional portions of said spring member being spaced apartto form a socket above said folded portion, said spring member mountedin said housing with a portion of said folded portion extendingexteriorally of said housing from one surface thereof, one of said twoadditional portions forming a deflectible beam, said det'lectible beamincluding a further spring portion extending from said deflectible beamat substan tially right angles thereto, said further portion includingbent portion means extending above another surface of said housing fordeflecting said deflectible beam upon depression of said bent portionmeans, said further portion being fixedly attached to said housing at apoint to the side of said bent portion away from said deflectible beam.

116. The connector of claim l wherein said folded portion includes twospring portions fixedly attached one to the other.

117. The connector of claim 15 wherein said housing is made from a solidblock of material having a vertical channel with narrow and widenedportions communicating with opposing surfaces of said block, and ahorilb zontal channel communicating with the widened portion of saidvertical channel, said spring member being inserted into said channels.

18. The connector of claim 15 wherein said bent portion is radiused.

19. The connector of claim 18 wherein the angle subtended by saidradiused bent portion is 20. The connector of claim 19 wherein saidextension includes a further radiused portion between said bent portionand said one spring portion.

2t. A method of mounting printing circuit boards comprising sandwichingsaid boards between electrical connec tors having pins extending fromone surface and sockets exposed at an opposing surface, said socketsadapted to receive pins projecting through an intermediate printedcircuit board from a connector immediately thereabove, said connectorscomprising a housing and a spring member folded on itself to provide apin and separated from itself above the folded portion to form a socket,one portion of the spring member forming a wall of said socket beingdeflectible towards an opposite wall, said one portion including anextension having a bent portion, said spring member being mounted insaid housing with said pin extending from a face of said housing andsaid bent portion extending above another face of said housing, the freeend of said bent portion being fixedly attached to said housing, andmeans for deflecting said one portion responsive to depression of saidbent portion, and depressing the bent portions of the connector byclamping the sandwiched boards and connectors together to secure matingpins and sockets.

22. A method of releaseably interconnecting printed circuit boardscomprising providing each printed circuit board with a hermaphoditicelectrical connector at opposite ends of said printed circuit board,each of said connectors having a pin extending from one surface and asocket exposed at an opposite surface, each of said pins beingelectrically connected to selected conductors on the printed circuitboard on which the connector is mounted; and

stacking said circuit boards carrying said connectors one on top of theother such that pins extending through a circuit board are inserted intocorresponding sockets of a connector mounted on a next adjacent circuitboard whereby a vertical sandwich structure of interconnected boards isformed, said hermaphoditic electrical connector comprising a housing anda spring member folded on itself to provide a pin and separated fromitself above the folded portion to form a socket, one portion of thespring member forming a wall of said socket being deflectable towards anopposite wall, said one portion including an extension having a bentportion, said spring member being mounted in said housing with said pinextending from a face of said housing and said bent portion extendingabove another face of said housing, the free end of said bent portionbeing fixedly attached to said housing, and means for deflecting saidone portion responsive to depression of said bent portion, anddepressing the bent portions of the connectors by clamping the stackedboards and connectors together to secure mating pins and sockets.

23 in combination a printed circuit board having conductive layersthereon, and

an electrical connector mounted at one end thereof,

said connector comprising a housing and an electrically conductivespring member, said spring member folded on itself to provide a pin andseparated from itself above the folded portion to form a socket, saidspring member being mounted in said housing such that said pin extendsfrom one surface of said housing and such that said socket communicateswith an opposing surface of said housing, one portion of the springmember forming a wall of said socket being deflectable towards anopposite wall, said one portion including an extension having a bentportion, the free end of said bent portion being fixedly attached tosaid housing, and means for deflecting said one portion responsive todepression of said bent portion.

24. The combination of claim 23 wherein said connector is mounted withsaid pin extending in a direction parallel to the plane of said circuitboard.

25. The combination of claim 23 wherein said connector is mounted withsaid pin extending through said circuit board.

26. The combination of claim 25 wherein said pin is connected to one ofsaid conductive layers at the point at which said pin extends throughsaid circuit board.

27. The combination of claim 25 and including means for connecting saidpin to a selected conductive layer on said circuit board and furtherincluding a number of board-connector combinations stacked one on top ofthe other with a pin from one circuit board extending into a socket of aconnector on a circuit board immediately thereunder.

28. The combination of claim 27 wherein one of the spring membersforming a wall of said socket includes an extension having a bentportion, said spring member 12 being mounted such that said bent portionextends above said opposing surface and is adapted to coact with thebottom of a circuit board immediately thereabove to deflect said onespring member into contact with the pin from the circuit boardimmediately thereabove.

29. The combination of claim 28 wherein a number of pins extend fromeach circuit board, whereby release of one circuit board-connectorcombination from an adjacent circuit board-connector combination iseasily effected.

30. In combination a hermaphroditic electrical connector of the typecomprising: a housing and an electrically conductive spring member, saidspring member folded on itself to provide a pin and separated fromitself to form a socket, one portion of the spring member forming adeflectible wall of said socket and including and extension having abent portion, said spring member being mounted in said housing such thatsaid pin extends from one surface of said housing, and such that saidbent portion extends above a second surface of said housing, said bentportion including means for deflecting said deflectible wall towards anopposite wall of said socket upon depression of said bent portion;

a body having a connector post depending therefrom and adapted to beinserted into the socket of said connector, said body having a surfaceadapted to coact with the bent portion of said connector to depress itwhen the housing of said connector and said body are forced together;and

means for maintaining said housing and body forced together thereby todeflect said one spring portion into contact with said post.

UNITED STATES PATENT OFFICE CETEFICATE 0F CORRECTION 0 PATENT NO. 3,923, 36;

DATED February 18, 1976 INVENTOR(S) Harold Rosen It is certified thaterror appears in the above-identified patent and that said LettersPatent 9 are hereby corrected as shown below:

Column 8, line 56 delete "upon", first occurrence. O

Signed and gcaled this twenty-seventh Day Of April 1976 Q [SEAL] Arrest.

RUTH c. MASON c MARSHALL DANN Augsrmg ("mlmiflimlvr flumnts andTrademarks

1. An electrical connector comprising: a housing and an electricallyconductive spring member, said spring member folded on itself to providea pin and separated from itself to form a socket, one portIon of thespring member forming a laterally deflectible wall of said socket andincluding an extension having a bent portion, said spring member beingmounted in said housing with said pin extending from one surface of saidhousing, said bent portion extending above a second surface of saidhousing and means for deflecting said one portion upon towards anopposite wall of said socket upon depression of said bent portion. 2.The connector of claim 1 wherein said folded portion includes two springportions fixedly attached one to the other.
 3. The connector of claim 1wherein said housing is made from a solid block of material having avertical channel with narrow and widened portions communicating withopposing surfaces of said block, and a horizontal channel
 4. Theconductor of claim 1 wherein said extension extends substantially atright angles to said one spring portion.
 5. The connector of claim 4wherein said extension includes a further radiused portion between saidbent portion and said one spring portion.
 6. The connector of claim 4wherein said bent portion is radiused.
 7. The connector of claim 6wherein the angle subtended by said radiused bent portion is 90*.
 8. Anelectrical connector comprising a housing, a spring member folded onitself to provide a pin and separated from itself above the foldedportion to form a socket, one portion of the spring member forming awall of said socket, being deflectable towards an opposite wall, saidspring portion including an extension having a bent portion, said springmember being mounted in said housing with said pin extending from a faceof said housing and said bent portion extending above another face ofsaid housing, the free end of said bent portion being fixedly attachedto said housing, and means for deflecting said one portion responsive todepression of said bent portion.
 9. The connector of claim 8 wherein thefolded portion of said spring member includes two spring portionsfixedly attached one to the other.
 10. The connector of claim 8 whereinsaid housing is made from a solid block of material having a verticalchannel with narrow and widened portions communicating with opposingsurfaces of said block, and a horizontal channel communicating with thewidened portion of said vertical channel and one of said opposingsurfaces, said spring member being inserted into said channels.
 11. Theconnector of claim 8 wherein said extension extends substantially atright angles to said one spring portion.
 12. The connector of claim 11wherein said extension includes a further radiused portion between saidbent portion and said one spring portion.
 13. The connector of claim 11wherein said bent portion is radiused.
 14. The connector of claim 13wherein the angle subtended by said radiused bent portion is 90*.
 15. Ahermaphroditic zero initial insertion and zero retraction forceconnector comprising: a housing; and, an electrically conductive springmember having a portion folded on itself, two additional portions ofsaid spring member being spaced apart to form a socket above said foldedportion, said spring member mounted in said housing with a portion ofsaid folded portion extending exteriorally of said housing from onesurface thereof, one of said two additional portions forming adeflectible beam, said deflectible beam including a further springportion extending from said deflectible beam at substantially rightangles thereto, said further portion including bent portion meansextending above another surface of said housing for deflecting saiddeflectible beam upon depression of said bent portion means, saidfurther portion being fixedly attached to said housing at a point to theside of said bent portion away from said deflectible beam.
 16. Theconnector of claim 15 wherein said folded portion includes two springportions fixedly attached one to the other.
 17. The connector of claim15 wherein said housing is made from a solid block of material having avertical channel with narrow and widened portions communicating withopposing surfaces of said block, and a horizontal channel communicatingwith the widened portion of said vertical channel, said spring memberbeing inserted into said channels.
 18. The connector of claim 15 whereinsaid bent portion is radiused.
 19. The connector of claim 18 wherein theangle subtended by said radiused bent portion is 90*.
 20. The connectorof claim 19 wherein said extension includes a further radiused portionbetween said bent portion and said one spring portion.
 21. A method ofmounting printing circuit boards comprising sandwiching said boardsbetween electrical connectors having pins extending from one surface andsockets exposed at an opposing surface, said sockets adapted to receivepins projecting through an intermediate printed circuit board from aconnector immediately thereabove, said connectors comprising a housingand a spring member folded on itself to provide a pin and separated fromitself above the folded portion to form a socket, one portion of thespring member forming a wall of said socket being deflectible towards anopposite wall, said one portion including an extension having a bentportion, said spring member being mounted in said housing with said pinextending from a face of said housing and said bent portion extendingabove another face of said housing, the free end of said bent portionbeing fixedly attached to said housing, and means for deflecting saidone portion responsive to depression of said bent portion, anddepressing the bent portions of the connector by clamping the sandwichedboards and connectors together to secure mating pins and sockets.
 22. Amethod of releaseably interconnecting printed circuit boards comprisingproviding each printed circuit board with a hermaphoditic electricalconnector at opposite ends of said printed circuit board, each of saidconnectors having a pin extending from one surface and a socket exposedat an opposite surface, each of said pins being electrically connectedto selected conductors on the printed circuit board on which theconnector is mounted; and stacking said circuit boards carrying saidconnectors one on top of the other such that pins extending through acircuit board are inserted into corresponding sockets of a connectormounted on a next adjacent circuit board whereby a vertical sandwichstructure of interconnected boards is formed, said hermaphoditicelectrical connector comprising a housing and a spring member folded onitself to provide a pin and separated from itself above the foldedportion to form a socket, one portion of the spring member forming awall of said socket being deflectable towards an opposite wall, said oneportion including an extension having a bent portion, said spring memberbeing mounted in said housing with said pin extending from a face ofsaid housing and said bent portion extending above another face of saidhousing, the free end of said bent portion being fixedly attached tosaid housing, and means for deflecting said one portion responsive todepression of said bent portion, and depressing the bent portions of theconnectors by clamping the stacked boards and connectors together tosecure mating pins and sockets.
 23. In combination a printed circuitboard having conductive layers thereon, and an electrical connectormounted at one end thereof, said connector comprising a housing and anelectrically conductive spring member, said spring member folded onitself to provide a pin and separated from itself above the foldedportion to form a socket, said spring member being mounted in saidhousing such that said pin extends from one surface of said housing andsuch that said socket communicates with an opposing surface of saidhousing, one portion of the spring member forming a wall of said socketbeing deflectable towards an opposite wall, said one portion includingan extEnsion having a bent portion, the free end of said bent portionbeing fixedly attached to said housing, and means for deflecting saidone portion responsive to depression of said bent portion.
 24. Thecombination of claim 23 wherein said connector is mounted with said pinextending in a direction parallel to the plane of said circuit board.25. The combination of claim 23 wherein said connector is mounted withsaid pin extending through said circuit board.
 26. The combination ofclaim 25 wherein said pin is connected to one of said conductive layersat the point at which said pin extends through said circuit board. 27.The combination of claim 25 and including means for connecting said pinto a selected conductive layer on said circuit board and furtherincluding a number of board-connector combinations stacked one on top ofthe other with a pin from one circuit board extending into a socket of aconnector on a circuit board immediately thereunder.
 28. The combinationof claim 27 wherein one of the spring members forming a wall of saidsocket includes an extension having a bent portion, said spring memberbeing mounted such that said bent portion extends above said opposingsurface and is adapted to coact with the bottom of a circuit boardimmediately thereabove to deflect said one spring member into contactwith the pin from the circuit board immediately thereabove.
 29. Thecombination of claim 28 wherein a number of pins extend from eachcircuit board, whereby release of one circuit board-connectorcombination from an adjacent circuit board-connector combination iseasily effected.
 30. In combination a hermaphroditic electricalconnector of the type comprising: a housing and an electricallyconductive spring member, said spring member folded on itself to providea pin and separated from itself to form a socket, one portion of thespring member forming a deflectible wall of said socket and includingand extension having a bent portion, said spring member being mounted insaid housing such that said pin extends from one surface of saidhousing, and such that said bent portion extends above a second surfaceof said housing, said bent portion including means for deflecting saiddeflectible wall towards an opposite wall of said socket upon depressionof said bent portion; a body having a connector post depending therefromand adapted to be inserted into the socket of said connector, said bodyhaving a surface adapted to coact with the bent portion of saidconnector to depress it when the housing of said connector and said bodyare forced together; and means for maintaining said housing and bodyforced together thereby to deflect said one spring portion into contactwith said post.